Apologies if I have missed it, but has the VisualOn AAC Encoder been checked out by you guys? It's recently been added in as an optional encoder for ffmpeg, but not sure how it compares to the great AAC encoders (one imagines it fares better than ffmpeg's current internal encoder)

The README of the library says:

QUOTE

VisualOn AAC encoder library

This library contains an encoder implementation of the Advanced AudioCoding (AAC) audio codec. The library is based on a codec implementationby VisualOn as part of the Stagefright framework from the GoogleAndroid project.

If you're in the mood grab it from (Edit: patent violation removed) and give it a test. Its little test app is simple and old school so writes out to ADTS AAC files rather than MP4. Usage Example: vo-aacenc.exe -r 128000 RhymePays.wav RhymePays.aac

I doubt it's great - but would be interested to know how far some good ears consider it behind the mighty Neros and Apples of this world....

What I tried was this song (and next song in this same album triggered the bogus bitstream bug). Quite easy to ABX at 320k.samp.zip ( 1.46MB )
Number of downloads: 155

Looking inside of resulting bitstream, you will find it's mostly padded with continuous NUL(0x00) bytes. You will effectively get half the size down or so just by compressing the resulting AAC with gzip or something.Therefore, audible quality at 320k is not surprising at all.